Granite Body Lots Of Spherical Weathering Metro Shield Construction Risk Analysis And Control

With the development of national economy,the increase of urban population, More and more cities begin building subway.The subway tunnel construction with shield s advantages are obvious.However, Shield generally adapte to homogeneous soil,soft rock or sand.In fact, Complex stratum is more common in the subway construction of our country. Because the shield is based on the geological features of "tailor—made", There is no guarantee that the shield is complete adaptation. In this sense, Construction risk is inevitable, How to minimize the risk,How to prevent the occurrence of significant risk accident are issues that people most concern.Globular weathering body is a typical complex stratum, Whict is common in GuangZhou and ShenZhen subway construction. The existence of globular weathering body, Not only stuck the cutter, wear and tear the tool, devite the driving axis,But also lead to the shield can,t drive, delay the construction duration.Therefore, To solve these problems, This paper mainly discuss the following aspects:(1) Analysis the formation mechanism,formation process,exploration methods,distribution of surface and underground and engineering properties.(2) Use the three—dimensional code recognition method to identify the main risk factors of shield construction in globular weathering body, Introduce the basic principles of Level—Fuzzy comprehensive evaluation method, Then, To ShenZhen Metro Line 5's shield interval of MinWu as an engineering example.Explain the application of Level—Fuzzy comprehensive evaluation method,And give the assessment result of main risk factors in the globular weathering body.(3) Propose the response to the major risks of shield construction in globular weathering body, Including surface pretreatment and underground rock broken with shield, and give the mechanical condition of rock with shield.(4) Finally, to two project as example, Explain the survey methods of globular weathering body; Surface pretreatment measures,Including Blasting,Breaking,Hrdraulic splitting machine,Manual digging artificial break and so on; Treatment measures in underground stratum reinforcement and open space with pressure to change cutter and tool.